Indespensable
by StarFormerAdira
Summary: Ratchet dares to question his own worth as a medic, so Optimus decides to show him how important he really is. TFP, slash, PWP - Ratchet/Optimus.


**A/N: This is just PWP! Just mindless slash! I started writing this as a side-project while still figuring out another story and I only came back to it a few days ago, and was surprised to find that I had finished it, so I sent it off to my lovely beta and it came back all sorted. So I thought, why not? Let's publish it and see what happens.  
To the aforementioned beta - thank you, GoldenJuiceBox, I really appreciate all you've done so far. If you like this, you'll like her fics too, so go check them out while you have some spare time! In the meantime, I hope you enjoy. **

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**Indespensible**

"There," Ratchet murmured, switching off the welder and taking a step back to admire his work. "You're all done."

Optimus flexed his hand cautiously, and then turned it over to examine his palm. Ratchet watched him silently, and met his gaze evenly when the Prime looked at him.

"Thank you," Optimus replied, in that beautifully deep bass tone of his. "You have done a good job."

Ratchet shrugged and let the welder drop from his hand onto the tray beside the berth Optimus was currently sitting on. The clattering sound was accompanied by the few other tools that lay there jumping a few inches into the air in response. Ratchet ignored them, however, turning to try and scrub the Energon off his fingers from Optimus's formerly-broken fuel line.

As he looked away, his patient stood silently, walking over to him with the stealth of a jungle cat. Ratchet's spark almost jumped out of its casing when he heard that voice alarmingly close to his audios – that smoothly velveteen voice that vibrated through Ratchet's own plating.

"You always do a good job," Optimus breathed, one hand ghosting along Ratchet's side while the other reached out to steady the wrist that was currently frozen in place. "You are indespensible. Do you know that?"

"I – I gathered as much," Ratchet managed to stammer out. His processor, normally so cool and logical, had been turned into a mess of feelings just by Optimus's proximity, and he no longer remembered what it felt like to have a cool core temperature.

Optimus softly nuzzled his neck, his lips moving against the wires there. "Good. I want you to know just how important to me you are."

Ratchet turned around, his back pressed against the table he had been working over, his hands braced against the blunt edges as he studied Optimus's face carefully.

The Autobot leader looked calmly back at the medic, betraying nothing through those shining azure optics of his. He was still too close for a normal conversation – but when had Ratchet ever thought this was going to be normal?

_Logic be damned_, he thought recklessly, letting himself indulge in a rare moment of following his feelings.

He smiled hesitantly at Optimus, perfectly aware of what he was about to do. "I'm sure there are other medics out there who are just as qualified as me."

A low growl rose from Optimus's throat and hung in the air around them, making Ratchet shudder from the vibrations, but he didn't stop. "Others who could do a better job, who could surpass me effortlessly. Are you sure I'm so important?"

Quick as a flash, Ratchet was picked up and deposited firmly but safely on the berth that Optimus had recently vacated. Said Autobot leader placed both hands on either side of Ratchet's helm and swung his leg over the medic's waist, keeping him held down. The restriction had quite the opposite effect it would usually have on Ratchet if it wasn't _Optimus _holding him down…_Optimus _looking so heated and dangerous with those burning narrowed optics…

Ratchet couldn't prevent an aroused gasp from slipping between his clenched dermaplates, and almost immediately, he felt beads of lubricant begin to gather around his interfacing equipment. One of Optimus's dark grey hands gathered both his wrists in a secure grip and pinned them above the red and white helm, making Ratchet simultaneously jolt with surprise and automatically arch up into Optimus's torso. The Autobot leader leant down and pressed a gentle, loving, barely there kiss to Ratchet's chevron, his glossa ghosting over the gleaming red paint.

Ratchet, quite literally, held his breath.

Then, as suddenly as Optimus had picked him up, a sweet, warm mouth engulfed the pointed tip of his right chevron and sent bullets of heat down his spinal strut.

Ratchet groaned needily as Optimus teased the various sensor nodes embedded into the surface of his chevrons, sucking on the blunt edges and generally making it a whole lot harder for the medic to keep his core temperature in check.

Except now, he found out that he didn't want to.

Oh, it was bliss. As Optimus braced his spare hand next to Ratchet's shoulder, Ratchet lost all sense of composure and let his next few breaths come out in desperate huffs, his legs raising to tangle with Optimus's. The Prime's sharp intake of breath indicated he was somewhat surprised at Ratchet's daring, but easily took advantage of it – he shifted so his codpiece was pressed _so damn arousingly _against Ratchet's own. His mouth didn't halt in its ministrations, except to trace a burning trail down Ratchet's cheek and begin to massage the taunt tubing and cables in his neck. Ratchet struggled half-heartedly against the restraint that held his hands captive, but Optimus refused to relent and instead his other hand moved down from Ratchet's shoulder to his thigh, curling around the back of his knee and hitching it up to rest teasingly on his hip.

Ratchet's breathing almost stopped, but Optimus didn't pause and soon the prone medic was softly groaning at the talented lips mouthing at his neck.

However, it all became too much when Optimus slowly, testingly ran his glossa up the full length of a fuel line by Ratchet's throat. The grey interface panel slid back, completely without Ratchet's permission, and the lubricant dripped a shining trail onto the berth beneath. Ratchet felt the embarrassment, no matter how lost it was in the pleasure, and averted his optics when Optimus glanced inquiringly up at him, fixing on a point in the suddenly very interesting ceiling above.

Surprisingly, Optimus released his hands and moved up so his codpiece was pressed very deliberately against Ratchet's open valve, the smooth curves of the heating metal almost protruding inside. Ratchet's hands immediately fell onto Optimus's shoulders, clenching his fists around the broad crimson shoulders until the tiniest dents appeared. Optimus barely noticed this – his piercing gaze was staring deep into Ratchet's blue optics as he pulled back and then…very gently, very hesitantly…pushed against Ratchet as his spike was already in that wet valve.

Ratchet pressed his dermaplates together, but it was no use. His body was betraying him and it was so unbelievably easy to just let that throaty moan hang in the air around them. The sound seemed to excite Optimus, who pushed again, both arms on either side of Ratchet's helm. The medic pressed upwards as he pushed, letting the droplets of lubricant smear against the still-closed interface panel, no longer embarrassed at his arousal. His own spike was so hard it was almost painful to keep it in its housing.

Ratchet let his helm fall back as Optimus gently retreated a few centimetres, letting the cool air wash across his plating and into his desperate valve. The Autobot leader brushed a gunmetal-grey finger across Ratchet's cheek, a soothing gesture and nothing more, but of course, the heat centring around Ratchet's lower torso deciphered it in entirely the wrong way. The medic could've sworn that he saw Optimus's lips twitch upwards into a rare smirk as the blue helmet ducked out of his sight. Ratchet was allowed a bare millisecond of confusion before a sudden but so _beautiful _intrusion into his valve made him cry out loud in ecstasy.

Oh, Primus, that felt _so good_.

With his hands on the inside of Ratchet's thighs, keeping them apart in the least painful way possible, Optimus had bent down and immediately pushed his glossa eagerly into the lubricant-stained port.

The taste of Ratchet tingled on the tip and Optimus lapped up all the lubricant that dropped from the edges, but now that there was actual stimulation going on, more and more of that addictive liquid was being produced and Optimus soon found that he was tasting as much of it as he could get. Meanwhile, up above, Ratchet moaned, gasped and even occasionally shouted out as Optimus licked his way around the nodes that lined his valve wall, firing them off as he went.

His spike extended as the clasps around it relented before they broke, and the gleaming shaft caught Optimus's attention as Ratchet let the relief of the lifted pressure roll over him. The Prime considered, absent-mindedly swirling his glossa around the clenching valve walls, and then he pulled out, raising his hands to wipe the lubricant away from his mouth, but a weak hand stopped him. Ratchet gripped his wrist and tugged him down until their bodies were flush against each other, and pressed his trembling lips to Optimus's, cleaning away the lubricant himself.

Optimus growled, deep in his throat, as the sweet liquid painted Ratchet's own glossa and he dove forwards, shoving their mouths together.

That was the final straw. Ratchet screamed against Optimus as he overloaded, his spike releasing a stream of transfluid, his port clenching desperately and his fingers, still on Optimus's shoulders, scrabbled for some sort of hold on sanity. Optimus pulled back, just watching, as heated bliss washed through Ratchet's entire body and his head fell back from Optimus's to land on the berth with a resounding _thunk._

But the Autobot leader wasn't done yet. The sight of his prized medic, writhing and moaning in such a beautiful overload was enough to get his charge up to an almost painful high. As Ratchet's optics began to light up again, he was treated to a most arousing sight. Optimus, straddling him, two fingers in his own valve and panting hot air all over Ratchet's burning body. The medic allowed himself a few seconds of indulgence before he got to his knees before Optimus, his port and spike still bared and gently closed his hand around Optimus's. The Prime looked at him almost desperately, and when Ratchet laid an experimental palm on his cable, Optimus groaned lustfully, thrusting into his grip, pulling the two digits out of his valve.

Ratchet didn't waste any time or energy. His core temperature was already rising, despite the fulfilling overload he'd just experienced, and as Optimus's spike slid, fully dripping, through his lax grip, he felt his own begin to harden again. The two Autobots were kneeling before each other on the lubricant-stained berth, and as Optimus began to lose any sort of strength to keep himself upright, Ratchet gently pushed him backwards, reversing the positions they had been in when he had recovered from his last release.

Optimus looked up at Ratchet, completely dominant above him, and knew this must be what the humans' heaven was.

Ratchet pulled backwards, and gently sheathed his spike into Optimus's slick valve. The Prime moaned as that wonderful sense of penetration overtook him and he arched upwards, into Ratchet, parting his legs as far as they would go. The red-and-white medic took a deep breath as Optimus's port walls clenched around him, and then pressed forwards until he was completely inside, his hands shaking from the pleasure. Optimus reached up and wrapped one arm around his lover's neck, the other on Ratchet's hips, urging him to move.

And he complied – that sensation of a fully erect spike moving through a velvet port was what drove Ratchet to the very brink. Knowing he was on the cusp of a second overload and determined to take Optimus with him, he thrust again and again, faster and faster, until the rhythm was commanding his body and all he had to do was respond. Every thrust was accompanied by a sharp gasp, and his valve was leaking copious amounts of lubricant on the already-beyond-salvaging berth.

"Ah! _Primus_!" Optimus had always been a little more vocal that Ratchet himself, but that was part of the ecstasy of this. The vibrations from his deep tone travelled down his body, through Ratchet's straining cable, triggering certain nodes that made Ratchet jerk with pleasure, almost faltering.

The medic could tell, by the dark navy of Optimus's optics, that he was so near overload. All he needed was a trigger to send him over the edge into complete and utter bliss – and when Ratchet found it, he didn't hesitate.

Moving one hand up from where it was braced against the berth underneath Optimus, he flexed his fingers and wrapped them around the Prime's cable once more.

Optimus's hips bucked and Ratchet almost lost his grip, but then began pumping the stiff spike as well as the smooth valve, feeling his own port walls clench in response. As the blunt edges of Ratchet's fingers scraped along Optimus's cable, overload hit with the force of a sledgehammer. Optimus arched his back, roaring out his release as his valve became almost impossibly tight and transfluid spurted out of his spike, splashing Ratchet's hand. As the wetness surrounding his own shaft contracted, Ratchet shouted in symphony with Optimus, vaguely aware of his own cool transfluid filling up the receiving port and the few droplets that escaped.

Optimus's hand slid limply from Ratchet's waist, dropping onto the surface below, and the Autobot leader groaned as his lover softly pulled out of him, stowing away his transfluid-stained cable and letting his interface panel slide back into place. Optimus tried to get up, but Ratchet refused to let him.

"Ratchet –" Optimus began curiously, but his protest was stopped by a set of swollen lips.

"It's your turn," Ratchet whispered, moving in harmony with Optimus's mouth but also slipping a few words in there as well. Optimus knew what Ratchet meant – he had only overloaded once, whereas Ratchet had been treated twice. He didn't even know if he could heat up again, his last release had been so intense, but Ratchet seemed intent on giving Optimus exactly what he himself had been getting.

"Come here," Ratchet ordered, pulling backwards from the kiss. Optimus surrendered his hand without a fight, but was surprised when Ratchet guided it to his own, open port, still brimming with his lover's transfluid. Optimus breathed in sharply as Ratchet smeared his silver digits with the plentiful liquid, and then, keeping his optics on Optimus's face to see his reaction, raised them to his mouth and gently enveloped the tip of the Autobot leader's index finger in his mouth.

Optimus let out a long, low moan.

Ratchet continued to suck off the sweet fluid, pausing occasionally to swallow, using his glossa as much as he could and making sure to dive into the small gaps between the armour, despite the tightness. He massaged the knuckle joints, the smooth, rounded tips and as he did that, one grey hand slid along Optimus's thigh to sneakily tweak at the circuits in his pelvic plating.

Optimus started as the pleasure pinged off his sensor net, and then relaxed again, allowing his head to fall back. Ratchet's fingertips scraped along his thigh, sending jolts of shuddering ecstasy up into his port and triggering a breathy groan. A deftly skilled hand reached out and ever so gently ran the length of the Prime's extended spike, already making transfluid dribble off the head. Optimus's fists clenched as he felt another charge begin to build up inside him, a charge that was aided by Ratchet, who gently teased the tip of his cable with ghosting caresses that managed to arouse Optimus more than anything he'd ever experienced. Spreading his legs to get as much of the beautiful feeling as he could, he was startled into shouting out as a dripping glossa wound its way up his spike, lips brushing against the heated appendage whenever Ratchet's glossa took a new turn.

"Ratchet!" His lover loved hearing Optimus cry out his name in the throes of the bliss he was administering. It gave him such a feeling of happiness, that he could bring such a noble and well-known mech like Optimus down to a level that everyone should experience. And he especially loved the fact that it was _him_, a nondescript, war-torn medic who was doing it. But in truth, he couldn't think of anyone who he would rather do this with than Optimus.

Ratchet demonstrated this intense feeling of bliss by suddenly moving to the very head of Optimus's cable and roving the tip of his glossa lovingly over the small slit there.

At this, the Autobot leader bucked his hips and flooded Ratchet's mouth with the sweet blandness of transfluid, but fireworks exploded inside Ratchet's stomach as he tasted every drop of it, the essence of his wonderful lover making him giddy. He swallowed all of the liquid, and licked up the remnants from Optimus's cable. Optimus reached down and gently touched Ratchet's cheek, using the simple touch to pull him forwards so their bodies were pressed against each other, then turning so Ratchet's back was against the berth and Optimus was on his side. Shutting his interface panel, the Prime reached up and gently stroked his lover's cheek, watching as Ratchet's optics slowly dimmed and his breathing slowed, recharge finally catching up on him. He moved closer to Optimus, moving his hand up to rest gently on the Autobot leader's shoulder, and gave a contented sigh when he felt a pair of lips brush gently across his chevrons again. This time, however, the touch was purely loving, and he was too tired to even try to interpret the feelings as arousing.

As Optimus began to slip into his own welcoming recharge, he rested his cheek on Ratchet's helm and made soothing circles on the small of the medic's back, lulling him to sleep.

Ratchet, despite this, shifted and grabbed Optimus's hand, holding it tight with his, keeping a little bit of his partner even as he caught up on some much-needed rest.

"Don't worry," Optimus whispered, still a little breathless from their interfacing session. "I'm not going anywhere."

This reassured Ratchet and, his grip only slightly slackening, his head relaxed against Optimus's chest and he finally drifted into unconsciousness.

"I'm not going anywhere," Optimus continued in a soft voice, "_ever_."

THE END

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**Yay! First slash fic, DONE! Please leave me a review and let me know what you think. It may inspire me to write more in the future...  
Quick disclaimer: I don't own Transformers or the characters. Unfortunately. **


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